Portable structure



June 18, 1968 c. F. HUDDLE 3,388,711

PORTABLE STRUCTURE Original Filed Aug. 29, 1963 INVENTOR.

United States Patent 3,388,711 PORTABLE STRUCTURE Carl F. Huddle, 3 Kenberton Drive, Pleasant Ridge, Mich. 48069 Original application Aug. 29, 1963, Ser. No. 305,483, new Patent Np. 3,215,153, dated Nov. 2, 1965. Divided and this application Oct. 15, 1965, Ser. No. 496,559

10 Claims. (Cl. 135-1) This invention relates to portable, prefabricated structures that may be classified as tentage. This application is a division of United States Patent application Ser. No. 305,483, filed Aug. 29, 1963, now Patent No. 3,215,153, which was a continuation-in-part application of application Ser. No. 286,563, filed June 10, 1963 and now abandoned. These shelters have many uses as temporary or semi-permanent structures, or they may be used as forms on which semi-permanent or permanent rigid structures may be constructed.

The object of this invention is to provide two or more simple frames to which a flexible membrane can be attached or supported by tension members between these frames, to form a warped roof that is well suited to meet weather requirements and is attractive in appearance. The enclosure between these frame members and the ground which would be called end walls can be optional or removable at will. The arches are attached to the base or to each other directly and positioned by an anchor system in an inclined position. Re-positioning of the arches and the roof as a unit may be accomplished after erection to suit conditions.

Other objectives are:

(1) To provide a tent-type structure with low wind resistance that is semi-rigid, to greatly decrease the stresses produced by wind impact loads.

(2) To provide a tent-like structure without interior obstructions.

(3) To provide a roof membrane in tension that can be sectionalized and is readily attachable to the frame .embers. This member can be strong and durable.

(4) To provide end walls that are optional or are detachable for changes in weather.

(5) In large structures, roof tension members such as cables or webbing can support the roof membrane between the frame members. These roof support members can be positioned by inverted tension members in the transverse direction. By such a system the roof tension members can be preloaded equally or unequally to prevent vibration, flutter or lift of the roof system as a whole or in part.

(6) To provide a structure that is easily and quickly assembled, erected, collapsed and disassembled.

(7) To provide a low-cost, economical structure that offers low wind resistance and is attractive in appearance.

(8) To provide a frame that can be sectionalized for transportation from one location to another.

(9) To provide a structure that can be designed with safety cables above the roof and between the frame members that will prevent collapse of the frame in case of the membrane or tension member failure between the frame members.

(10) To provide an inexpensive form on which a rigid shell structure may be constructed.

(11) To provide a structure that is adaptable to pass through traflic, which is desirable for servicing vehicles or airplane hangars.

(12) To provide an inexpensive flexible glamorous warped-surface prefabricated structure that is suitable for expositions, fairs, shows, etc.

(13) To provide a structure simplicity of design.

that is beautiful in its 3,383,?11 Patented June 18, 1968 (14) To provide a structure that lends itself to natural ventilation due to its shape or the sag in the roof system.

The foregoing objectives and advantages of this invention are achieved by a portable prefabricated structure comprised of members that are so positioned in relation to each other that they produce a warped contour on a membrane stretched between them. The wind resistance of this structure is thereby lowered considerably, and, in addition, the semi-rigidity or the resiliency of the struc tural system enables it to take the uneven impact wind loads without producing the high stresses that would occur in a rigid structure. The importance of these factors was discovered in the study of test models and full-scale structures of the configurations described herein and is the principal reason for this divisional application.

This limited flexibility or semi-rigidness in the structure is achieved by the use of the curved arches that are erected to a position where they are inclined with the base to enable the use of longer arch legs. These long arches, when so inclined with the base, can be so designed that the compressive load is negligible when the column slenderness ratio of the legs is high. Thus, the critical forces are in bending, and when tension members such as fabric, cables or semi-rigid materials are used in or for the roof system (between the arches) and for the anchoring system (between the arches and the ground or base), the entire structure can develop a semi-rigidity and resiliency, but in such a manner that it resists any movement that is produced by outside forces, such as a wind, with much less stress in the supporting arches than would result if the arches were strictly rigid. By such a structure, then, two of the most detrimental factors of portable structures, high wind resistance and inability to absorb wind impact loads, are greatly diminished.

Other advantages may appear minor but at times are very desirable. Some of these are an unobstructed interior, open ends for pass-through trafiic, portability, drainage away from the ends, and the flexibility of design by the use of various curved arches and various inclinations of the arches (with the base) to achieve many different or aesthetic structures. Also, round tubing or tube bundles that have the same moment of inertia in all directions seem to be ideal for arch construction.

This invention is further described with reference to the accompanying drawing where FIG. 1 is a side elevation of this portable structure, FIG. 2 is the end elevation from position 2-2, and FIG. 3 is an isometric view of the structure having a cut-away section of the membrane or skin. In all figures, the curved arches 5 and 6 are shown inclined from a common base or surface, pivotably tilted outward by pivot means not shown herein but described and shown in the aforementioned divisional application from each other with a membrane or skin 4 attached to the tilted arches and stretched or teusioned between the arches by the weight of the arches themselves and an er;- terior anchoring system. The anchoring members can be a column 7, a multiplicity of columns, cables, etc., an end wall enclosure such as 8, or a combination of such members. The end wall can serve as a tension member between the arch and the base.

Such a combination of curved arches, a membrane, and a positioning or anchoring system produce the warped surface in the membrane 4. In some structures, it may be desirable to support the membrane by longitudinal tension members it) between the arches and inverted tension members 9 to shape the surface of membrane and/ or to provide a grid to which the membrane may be attached.

When the membrane or skin is attached to either tension members 94% between the arches, the membrane can be prevented from ballooning due to wind forces. As

can be seen, a membrane and inverted tension members can be supported by the tension members 10 between the arches so that the root can carry heavier loads.

It is desired to point out that the feet of the inclined arches are attached to the base or to each other to take the arch thrust load. In the latter case they may rest on the base which opposes the vertical component of the thrust force. When the feet of the opposing arches are attached indirectly to each other through the base, they can be adjacent or widely separated.

It will be appreciated that the angularity of the arch members 5 and 6 need not be substantially identical to achieve symmetry of the structure. One of the arch members, for example, may be elevated to a greater angle.

whereas the opposite arch member may be elevated to a lesser angle to obtain the desired aesthetic contour of the structure and the requisite headroom as may be required, depending on the use to which the structure is to be subjected. Variations in the angular disposition of the arch members is also desirable and constitutes a further advantage of the structure comprising the present invention enabling the configuration of the structure to be varied consistent with prevailing weather and wind conditions so as to provide optimum shelter and stability of the unit. Such variations in the angularity of the opposing arches can simply be achieved by controlling the lengths of the restraining cables 7.

From the description and drawings, it can be seen that the minimum number of arches is two, but three, four or more arches can be used by inclining them outward from each other away from a center point. In the use of a multiplicity of arches, a top view of such structures would be similar to a three leaf clover (three arches), a four leaf clover (four arches), etc.

It is also practicable in some cases to use intermediate supports for the roof system (between the inclined arches) to get higher headroom or to give added support to the roof system.

I claim:

1. A portable, semi-rigid structure comprising a plurality of arches with formed bight sections, means for pivoting said arches, said arches being inclined from a common base and pivotably tilted outward about said pivot means from each other, a flexible membrane attached to said arches and stretched between them in such a manher as to form a warped surface for the roof of the structure, and means for anchoring said arches to said base for restraining said flexible membrane in tension.

2. The structure described in claim 1 wherein said flexible membrane is supported by a tension system between said arches.

3. The structure described in claim 2 wherein the flexible membrane and the supporting tension system are held in position by inverted tension members.

4. The structure described in claim 1 wherein said anchoring means is fixedly secured to both the perimeter of the roof membrane and the base.

5. The structure described in claim 1 wherein said flexible membrane is supported on a plurality of longitudinal members connected between said arches.

6. The structure described in claim 1, wherein one of said arches is higher than the other of said arches.

7. A portable structure composed of a plurality of arches, means for pivota'bly mounting said arches, said arches being variably inclined from a common base and pivotably mounted outward about said mounting means away from each other, a plurality of tension support members attached to said arches, a roof membrane mounted on said tension support members between said arches, and an anchoring system, said roof membrane and said support members being tensioned and positioned by said anchoring system to the base.

8. The structure described in claim 1 including, additionally, intermediate positioning members for said tension support means. i

9. A portable structure comprised of two arches having curved bight sections, means for pivoting said arches, said arches being inclined from a common base and pivotably tilted outward about said pivot means from each other and forming a non-continuous frame, a flexible membrane attached to said arches and stretched between them to form a warped roof surface, and an anchoring system to restrain said inclined arches from moving away from the base and to tension the roof membrane.

10. The structure described in claim'9 including, additionally, transverse tension members that extend across the arches and are confined between said flexible membrane and said curved arch support members.

References Cited UNITED STATES PATENTS I 2,928,360 3/1960 Heine 52-80 2,961,802 11/1960 Morgan et a1. 52-80 3,143,122 4/1964 Goodrich -3 3,215,153 11/1965 Huddle 1354 2,797,696 7/1957 Futsche 135-1 2,963,031 12/1960 Carroll l357.1 X 3,035,591 5/1962 Patten 135-4 X 3,255,467 6/1966 Kowalski 135-5 FOREIGN PATENTS 1,308,293 9/ 1962' France.

966,344 7/ 1957 Germany. 967,000 9/1957 Germany.

- OTHER REFERENCES Engineering News-Record, Aug. 11, 1955, page 23.

DAVID J. WILLIAMOWSKY, Primary Examiner.

HARRISON R. MOSELEY, I. KARL BELL,

Examiners. L. J. SANTISI, Assistant Examiner. 

1. A PORTABLE, SEMI-RIGID STRUCTURE COMPRISING A PLURALITY OF ARCHES WITH FORMED BIGHT SECTIONS, MEANS FOR PIVOTING SAID ARCHES, SAID ARCHES BEING INCLINED FROM A COMMON BASE AND PIVOTABLY TILTED OUTWARD ABOUT SAID PIVOT MEANS FROM EACH OTHER, A FLEXIBLE MEMBRANE ATTACHED TO SAID ARCHES AND STRETCHED BETWEEN THEM IN SUCH A MANNER AS TO FORM A WARPED SURFACE FOR THE ROOF OF THE STRUCTURE, AND MEANS FOR ANCHORING SAID ARCHES TO SAID BASE FOR RESTRAINING SAID FLEXIBLE MEMBRANE IN TENSION. 